The company was formed by the January 2011 merger of two predecessor companies, Acergy S.A. and Subsea 7, Inc.[6][7] Acergy was founded in 1970 as Stolt Nielsen Seaway, a division of the Norwegian Stolt-Nielsen Group offering divers for the exploration of the North Sea.

After a series of acquisitions, including Comex Services of France in 1992 and Houston, Texas–based Ceanic Corporation in 1998, the company changed its name to Stolt Offshore in 2000.

Five years later Stolt-Nielsen spun out the company as an independent business listed on the Oslo Stock Exchange and NASDAQ.

The new entity took the Subsea 7 name while retaining Acergy's Luxembourg domicile and operational headquarters in London.

The current headquarters for Subsea 7 is located at 40 Brighton Road, Sutton, London.